Return to News

Why invader species may be taking dinner off your table

by Angela Herring

The species that live on our coasts pro­vide ben­e­fits that most of us are unaware of. Oyster reefs, for example, sta­bi­lize the shore­line from ero­sion and keep the water clean through fil­tra­tion. Kelp forests pro­vide food for eco­nom­i­cally impor­tant fishes—ones that we also love to eat.

So what hap­pens when the kelp forest is taken over by non-​​native ascid­ians, or sea squirts, that hitched a ride from China to Maine on the hull of a ship­ping vessel? The kelp forest is destroyed, the fish­eries are dev­as­tated, and our wal­lets and dinner plates are left empty.

While coastal species are dealing with new chal­lenges like climate-​​related ocean acid­i­fi­ca­tion, they’re also working with the same stres­sors they’ve faced for cen­turies, according to David Kimbro, an assis­tant pro­fessor of envi­ron­mental sci­ences at Northeastern’s Marine Sci­ence Center. Since the days of Columbus, glob­al­iza­tion has brought with it for­eign invaders that can out­com­pete native species both on land and in the sea.

“From basic prin­ci­ples, we know that marine and ter­res­trial sys­tems differ fun­da­men­tally,” said Kimbro. But despite those dif­fer­ences, marine man­age­ment strate­gies have been based only on find­ings from ter­res­trial research.

That’s because sim­ilar work on marine sys­tems simply hadn’t been car­ried out—until now. In a paper recently pub­lished in the journal Ecology Let­ters, Kimbro and his col­leagues at the Uni­ver­sity of Cal­i­fornia at Davis syn­the­sized nearly two decades’ worth of data from exper­i­mental marine ecology. With this so-​​called “meta-​​analysis” of other researcher’s work, the team was able to draw new con­clu­sions about the impacts of marine inva­sive species.

They found that the fac­tors impor­tant to a for­eign ter­res­trial species’ suc­cess are very dif­ferent from those for a for­eign marine species. For example, native plants tend to be good at out­com­peting for­eign invaders, Kimbro said. But the same is not true of marine plants, which can’t out­com­pete the inva­sive algae that com­monly plague their habi­tats. On the other hand, her­bivory, or plant con­sump­tion by ani­mals, is a strong con­trol­ling factor both on land and in the sea.

Of course, not all for­eign species are prob­lem­atic, as Kimbro pointed out. Corn is a good example: Though it’s grown all over the world, and we depend on its suc­cess for our own liveli­hood, it’s native to only a small area of Cen­tral America.

“Regard­less of whether we’re talking about a good or bad invader, we want to know what allows them to suc­ceed or what inhibits their suc­cess,” Kimbro said, adding that both are crit­ical to main­taining healthy and eco­nom­i­cally sound ecosystems.

Originally published in news@Northeastern on March 26, 2013

« »